Abstract. The analysis of the unexpected ionospheric phases before large earthquakes is a popular approach in earthquake prediction studies. In this study, the Total Electron Content (TEC) data of five International GNSS Service (IGS) stations and the Global Ionosphere Maps (GIMs) were used. The Short-time Fourier Transform (STFT) and a running median process were applied on the TEC time series to detect abnormalities before the Mw7.3 Iran-Iraq border earthquake on November 12, 2017. The analyzes showed positive anomalies 8–9 days before the earthquake and some positive/negative anomalies 1–6 days before the earthquake. These anomalies were cross-checked by space weather indices Kp, Dst, F10.7, Bz component of the interplanetary magnetic field (IMF Bz), electric field (Ey), and plasma speed (VSW). The results showed that the anomalies 1–6 days before the earthquake caused by a moderate magnetic storm. Also, the positive anomalies 8–9 days before the earthquake should be related to the Iran-Iraq border earthquake due to quiet space weather, local dispersion, and proximity to the epicenter.